For everything alienable must be capable of being acquired by anyone.The rightfulness of acquisition, however, rests entirely upon the form in accordance with which what is in possession of another, is transferred to me and accepted by me.In other words, rightful acquisition depends upon the formality of the juridical act of commutation or interchange between the possessor of the thing and the acquirer of it, without its being required to ask how the former came by it; because this would itself be an injury, on the ground that: Quilibet praesumitur bonus.Now suppose it turned out that the said possessor was not the real owner, I cannot admit that the real owner is entitled to hold me directly responsible, or so entitled with regard to any one who might be holding the thing.For I have myself taken nothing away from him, when, for example, I bought his horse according to the law (titulo empti venditi) when it was offered for sale in the public market.The title of acquisition is therefore unimpeachable on my side; and as buyer I am not bound, nor even have Ithe right, to investigate the title of the seller; for this process of investigation would have to go on in an ascending series ad infinitum.
Hence on such grounds I ought to be regarded, in virtue of a regular and formal purchase, as not merely the putative, but the real owner of the horse.
But against this position, there immediately start up the following juridical principles.Any acquisition derived from one who is not the owner of the thing in question is null and void.I cannot derive from another anything more than what he himself rightfully has;and although as regards the form of the acquisition the modus acquirendi- I may proceed in accordance with all the conditions of right when I deal in a stolen horse exposed for sale in the market, yet a real title warranting the acquisition was awanting; for the horse was not really the property of the seller in question.However Imay be a bona fide possessor of a thing under such conditions, I am still only a putative owner, and the real owner has the right of vindication against me (rem suam vindicandi).
Now, it may be again asked, what is right and just in itself regarding the acquisition of external things among men in their intercourse with one another- viewed in the state of nature according to the principles of commutative justice? And it must be admitted in this connection that whoever has a purpose of acquiring anything must regard it as absolutely necessary to investigate whether the thing which he wishes to acquire does not already belong to another person.For although he may carefully observe the formal conditions required for appropriating what may belong to the property of another, as in buying a horse according to the usual terms in a market, yet he can, at the most, acquire only a personal right in relation to a thing (jus ad rem) so long as it is still unknown to him whether another than the seller may not be the real owner.Hence, if some other person were to come forward and prove by documentary evidence a prior right of property in the thing, nothing would remain for the putative new owner but the advantage which he has drawn as a bona fide possessor of it up to that moment.Now it is frequently impossible to discover the absolutely first original owner of a thing in the series of putative owners, who derive their right from one another.Hence no mere exchange of external things, however well it may agree with the formal conditions of commutative justice, can ever guarantee an absolutely certain acquisition.
Here, however, the juridically law-giving reason comes in again with the principle of distributive justice; and it adopts as a criterion of the rightfulness of possession, not what is in itself in reference to the private will of each individual in the state of nature, but only the consideration of how it would be adjudged by a court of justice in a civil state, constituted by the united will of all.In this connection, fulfillment of the formal conditions of acquisition, that in themselves only establish a personal right, is postulated as sufficient; and they stand as an equivalent for the material conditions which properly establish the derivation of property from a prior putative owner, to the extent of making what is in itself only a personal right, valid before a court, as a real right.Thus the horse which I bought when exposed for sale in the public market, under conditions regulated by the municipal law, becomes my property if all the conditions of purchase and sale have been exactly observed in the transaction; but always under the reservation that the real owner continues to have the right of a claim against the seller, on the ground of his prior unalienated possession.
My otherwise personal right is thus transmuted into a real right, according to which I may take and vindicate the object as mine wherever I may find it, without being responsible for the way in which the Seller had come into possession of it.
